China’s Olympic champion Sun Yang showed a softer side to his gnarly public image on Sunday by lavishing compliments on rival Japanese swimmer Kosuke Hagino at the Asian Games.

The towering Chinese topped the time sheets in the morning’s 200 metres freestyle heats in Jakarta in a leisurely one minute, 47.58 seconds before being reminded about an unseemly diplomatic row he sparked at the last Asian Games in 2014.

Furious after being ambushed by Hagino in the 200m free in Incheon, Sun branded Japan’s national anthem “ugly” – not the first time the three-time Olympic gold medallist has become involved in a war of words.

“Look, I think Hagino is a good guy,” Sun told reporters. “The way he swims the individual medley is an inspiration to me. We should be working together to raise the level of Asian swimming.

“Today was a good first swim, very satisfied. The Asian Games isn’t the biggest competition perhaps but it’s an important stepping stone towards the world championships and the 2020 Tokyo Olympics.”

His part-time coach Denis Cotterell said the giant Chinese was pacing himself with further individual races to come in the 400m, 800m and 1,500m free.

“That was just a very safe swim,” the Australian said. “He was slow off the blocks and just did what he had to do.

“He’s got a long programme so it’s early days,” added Cotterell. “We’ll know more about where he’s at at the end of the meet.”

Hagino, who won Olympic gold in the 400m individual medley in Rio two years ago, failed to qualify for the 200m freestyle at this year’s Asian Games.

Jordan’s Khader Baqlah, who has trained alongside American stars Caeleb Dressel and Ryan Lochte at the University of Florida, posted the second quickest time behind Sun in 1:47.60.

Defending champion Daiya Seto qualified fastest for the 200m butterfly final in 1:57.23 from fellow Japanese Nao Horomura, who also won his heat in 1:58.06, edging out India’s Sajan Prakash.

“I can definitely go quicker,” said Seto, who also won Pan Pacific gold in Tokyo earlier this month.

“It was about conserving energy. The key tonight will be to be brave and go for it.”